Endoscopic mucosal resection (EMR) was pioneered in Japan for management of early gastric cancer (Tada M., Murakami A., Karita M. et al. Endoscopic resection of early gastric cancer. Endoscopy 1993; 25: 445-50.). This procedure has gained wider acceptance as a therapeutic option for various gastrointestinal lesions, including Barrett's esophagus (i.e. intestinal metaplasia of the esophagus, a precancerous pathology), and colorectal adenomas and early cancers. It can also be extended to treat intestinal metaplasia of the gastric antrum, which is also precancerous, and which often persists after treatment of Helicobacter pylori (Helicobacter pylori associated gastric intestinal metaplasia: Treatment and surveillance. Liu K S H, Wong I O L, Leung W K. World J Gastroenterol. 2016; 22(3): 1311-1320), a known cause of chronic gastritis, gastric intestinal metaplasia, and gastric cancer.
Chromoendoscopy using an appropriate staining dye, such as methylene blue, is used to identify the mucosa with intestinal metaplasia, a lesion. 0.5% methylene blue is sprayed through a cannula onto the mucosa at least around the area of a lesion. This is followed about two minutes later by vigorous washing of the mucosa. Mucosa with intestinal metaplasia remains persistently stained at the lesion despite the washing.
Typical existing techniques of endoscopic mucosal resection use a single standard endoscope with specially designed, commercially available endoscope caps. Examples of such techniques and of the endoscopes used to perform the techniques are described in “Endoscopic Mucosal Resection” by J. H. Hwang et al. in Vol. 82, No. 2:2015, Gastrointestinal Endoscopy, pp. 215-226, and in “Endoscopic Ultrasound and Endoscopic Ultrasound-Guided Fine Needle Aspiration Cytology,” a portion of Chapter 33 of Clinical Gastrointestinal Endoscopy, Second Edition, Ginsberg et al., 2005, 2012, entitled “Endoscopic Therapy for Gastric Neoplasms,” Ryu et al., on page 431, the immediately preceding printed publication source corresponding to the online source referenced in the originally filed specification.
Endoscopes with two biopsy channels, rather than one biopsy channel are known.
Endoscopes with two biopsy channels are generally not available in normal endoscope theaters because the need for such endoscopes is infrequent, their size is bulky, and their cost is high.
Cap-assisted EMR typically uses submucosal injection to lift the target lesion at the mucosa. Dedicated mucosectomy devices that use a cap affixed to the distal tip of the endoscope are available. The cap is usually equipped with a specially designed, crescent-shaped electrocautery snare that is opened and positioned on an internal circumferential ridge at the tip of the cap. The endoscope is then positioned immediately over the target lesion, suction is used to retract the mucosa into the cap, and the snare is closed to capture and resect the lesion. Because no ligation is used after the retraction and before the snare is closed, and because the resection area is broad-based, bleeding can be a complication.
Ligation-assisted EMR uses a banding cap attached to the distal open end of the endoscope and positions the cap over the target lesion with or without prior submucosal injection. Suction applied to the endoscope causes the lesion to be sucked into the cap. A band is deployed from a band ligator equipped with a band to ligate the lesion to form an artificial polyp. That polyp is then resected using a specially designed snare through the banding device.
If no submucosal injection is used, the suction on the lesion could include submucosa and the layers underneath, so that perforation can be a complication. If needle injection is used, the needle injection needs to be performed within the confined size of the cap and the needle is likely to be in a vertical orientation over the lesion, so that positioning the needle accurately in the submucosal layer is not readily accomplished, and good elevation of the mucosa may not be achieved, posing a danger to subsequent EMR.